The present invention relates to a gate valve, a sealing gasket for the valve, and a method of assembling the valve. More specifically, the present invention relates to a sliding gate valve such as may be used to govern the flow of a fluid such as a liquid or a gas. Example fluids suitable for use with the valve of the present invention include water, air, or oxygen. The fluids may or may not be pressurized as the valve of the present invention provides a seal against leakage that is not dependent upon a pressure differential. Typical installations for the valve of the present invention include, but are not limited to, household water supply systems, laboratory environments, and industrial settings.
The present invention is a sliding gate valve that may be comprised of a valve body having an inlet and an outlet, a cavity extending longitudinally through at least a portion of the valve body, a gate that is slidably moveable within the cavity, and at least one sealing gasket providing a seal between the gate and the cavity. Flow of a fluid through the valve is typically from an inlet to an outlet. Typically, the flow is generally transverse to the longitudinally extending cavity of the valve wherein the slidably movable gate can move to either an open or a closed position. Preferably, the sliding gate valve of the present invention is provided with a gate having a blocking portion and a conduit portion. Typically, flow through the valve does not occur if the blocking portion of the gate is aligned between the inlet and outlet of the valve. Typically, flow through the valve is able to occur if the conduit portion of the valve is aligned between the inlet and outlet of the valve.
The sealing gasket of the present invention discourages unintended releases of a fluid from the valve of the present invention. The sealing gasket provides a seal between a portion of the sliding gate and a portion of the cavity of the valve body. The sealing gasket may be a typical o-ring, such as an o-ring having a round cross-section. The sealing gasket of the present invention may be comprised of two separate sealing devices, such as a pair of concentric o-rings. In this embodiment, one of the o-rings would provide a seal between the cavity of the valve body and the perimeter of the conduit portion of the gate. The second o-ring would provide a seal between the cavity of the valve body and a perimeter surrounding the conduit portion and the blocking portion of the gate. In this manner, an unintended release of fluid from the valve of the present invention is discouraged, even as the position of the gate is slidably moved in the cavity between an open position and a closed position.
Preferred embodiments of the valve of the present invention may be comprised of a groove on a surface of the cavity adapted to receive at least a portion of the sealing gasket. Alternatively, embodiments of the valve of the present invention may be comprised of a groove on a surface of the gate that is adapted to receive at least a portion of the sealing gasket. A sealing gasket in either position would govern the seal between an opposing surface on the gate or the cavity, respectively. In addition, alternative embodiments of the present invention may have a second sealing gasket on a second surface of the cavity or the gate. This second sealing gasket would be positioned to govern a seal between a second opposing surface on the gate or the cavity, respectively. In addition, the second surface of the cavity or the gate may also be comprised of a groove adapted to receive at least a portion of the sealing gasket.
Alternative embodiments of the present invention may utilize one sealing gasket to produce a seal between a gate surface and its opposing cavity surface. A second sealing gasket may be used on the opposite side of the gate or cavity in order to produce a seal between its opposing cavity surface or gate surface, respectively. The singular sealing gasket in this embodiment may be comprised of a circular portion connected to at least one straight portion. Typically, the circular portion would extend around a perimeter of the conduit portion of the gate. An alternative embodiment provides for a sealing gasket comprised of a circular portion, at least one straight portion connected to the circular portion and a curved portion connected to the straight portion. Another alternative embodiment provides for a sealing gasket comprised of a circular portion, at least one straight portion connected to the circular portion and a substantially semicircular portion connected to the straight portion. Another alternative embodiment of the present invention provides for a sealing gasket comprised of a circular portion, at least one straight portion connected to the circular portion, at least one additional straight portion connected to the circular portion and a substantially semicircular portion having a first end and a second end. In this embodiment, the straight portions are tangential to the circular portion at their respective connections to the circular portion; in addition, the two straight portions are parallel. Additionally, the ends of the two straight portions are connected to opposite ends of the substantially semicircular portion.
Another embodiment of the sealing gasket of the present invention provides for a gasket comprised of a circular portion; first connector and second connector portions, each connected to the circular portion at their respective first ends; and a substantially curved portion having ends that are connected to one each of the second ends of the first and second connector portions. Another embodiment provides for a sealing gasket to surround both the perimeter of the conduit portion of the gate and the perimeter of the blocking portion. This embodiment is preferably a one-piece gasket that may have a portion of the gasket intended to isolate the respective perimeters of the conduit and the blocking portions. This sealing gasket may be comprised of any combination of curved or straight portions. For example, a sealing gasket of the present invention may be comprised of straight portions producing a shape resembling a blocked numeral eight. Alternatively, a sealing gasket may be comprised of circular portions sharing a common tangential border, thus resembling a pair of connected circles.
Any of the sealing gaskets of the present invention may be comprised of a material suitable for a use of the valve. For example, certain materials are more resistant to degradation in the presence of petroleum-based products. Examples of materials that may comprise the sealing gasket of the present invention include, but are not limited to: neoprene, rubber, isoprene, Teflon®, nitrile, silicone, fluoroelastomer such as Viton®, EPDM, EPM, styrene-butadiene, butyl, and CSM such as Hypalon® elastomer.
Portions of the sliding gate valve, such as the valve body and the gate, may be comprised of a material suitable for a particular use of the valve. As mentioned above, certain materials are more resistant to degradation in the presence of petroleum-based products. Examples of materials that may comprise the valve body or the gate of the present invention include, but are not limited to: plastic, PVC, CPVC, ABS plastic, polypropylene, polyethylene, metal, copper, aluminum, stainless steel, cast iron, and other typical piping and plumbing materials. The materials used for portions of the sliding gate valve may be manufactured using typical methods such as injection molding, casting, machine milling, and shaping.
Additionally, the valve may be comprised of at least one post operatively attached to an end of the sliding gate. If the valve has two posts, preferably the posts are attached to opposite ends of the gate. Typically, the posts may be used to move the gate between the open and closed positions for the valve. A post may additionally comprise an indicator of the position of an attached gate as an indicator of an open or closed valve. In addition, a post may be comprised of an end cap that may include an indicator of the gate position as an indicator of an open or closed valve. For example, a post or an end cap may include markings or printing of symbols or text on that element. Alternatively, a post or end cap may be colored to indicate a gate position. For example, a post or end cap may be colored green or red as an indicator of an open valve or closed valve, respectively.
The inlet and outlet of the valve of the present invention may be comprised of any typical pipe connection. Exemplary pipe connections include, but are not limited to: mechanical connections, threaded connections, sockets, Victaulic®, flanges, welded connections, glued connections, compression fittings, banded connections, swaged flangeless connections, hydraulic connections, and other plumbing connections.
A method of assembling an exemplary valve of the present invention is facilitated by two posts that are connected to opposing ends of a gate. The preferred gate of this example would be comprised of a pair of posts having different sizes and/or shapes. In this example, the valve body is additionally comprised of an aperture in the valve body that extends into the cavity allowing for the slidable assembly of the gate into the cavity. This aperture may be sealed with a cap or other similar device so that the sealed cavity secures the gate of the valve during its movement between an open or closed position. Preferably, the cap has an opening sized so as to provide a complementary fit for only one of the posts attached to the gate. Near an opposite end of the cavity, a second opening is provided that provides a complementary fit for the other post attached to the gate. During assembly, the gate is preferably installed by sliding it in a direction generally aligned with the longitudinal length of the cavity. Then, the cap or other sealing assembly is used to seal the aperture of the cavity. A correctly installed gate would have each of the posts on the gate installed in their respective complementary sized openings. As a result, the gate would be properly positioned for movement within the cavity that would preferably correspond with any exterior markings on the valve that indicate an open or closed state. In addition, by observation of the posts properly placed into complementary sized openings, the valve may be identified as having been properly assembled in the absence of any markings.
Alternatives to the different sized or shaped posts of an example embodiment of the present invention provide for a first post being smaller than a second post or a first post having a different cross-sectional shape than a second post. In this manner the method of assembly may be further specified by the use of the different posts. For example, if a first complementary sized opening near an end of the cavity—that is sized to fit a first post on the gate—is smaller than a second post on the gate; the second post will not fit into the first complementary sized opening. As a result, the proper assembly of the valve is dictated by requiring a reversal of the gate so that the properly fitted first post will be placed into the first complementary sized opening. Then, the cap or other sealing device can be placed over the aperture in the valve body. In turn, the second larger post will be properly accommodated in a second complementary sized opening in the cap, thus producing a properly assembled embodiment of the sliding gate valve of the present invention.
An alternative method of assembly of the valve of the present invention provides for the assembly of two portions of a valve body formerly separated in the vicinity of the cavity of the valve to allow for installation of the gate. Preferably, the former separation between the two portions of the valve body would not be in the area of a sealing surface between the cavity and the gate. An exemplary embodiment of the valve of the present invention assembled by this method may use two nearly symmetrical portions of the valve body that would have been separated along a longitudinal plane that follows the cavity of the valve. The portions of the valve body may be sealed together by a mechanical seal or supplemented by additional sealing means such as gaskets, glues, epoxies, welding, clamps, bands, screws, or bolts. The portions of the valve body may also use pins or other means of guiding and assuring a proper assembly of the valve body portions.